Commercial FG-57 dental carbide burs will be coated with several refractory intermetallic compounds (borides and carbides) by RF sputter deposition. The coated burs will be evaluated for any improvement in performance (initial cutting rate and durability) by means of a standardized milling test (300,000 rmp; 50, 100 and 150 gm load; 2 mm depth of cut; 1 cm cuts) using two work materials, a 50 percent diatomaceous earth filled phenolic and soda-lime glass. Attempts will be made to delineate that combination of coating material, deposition parameters and thickness which provide optimal improvement in performance. Additional samples of burs from different manufacturers will be coated with the optimal coating to determine the effects of bur variability in carbide composition, flute design and edge sharpness on the (presumed) range of improvements to be obtained by hard coating.